Hundreds of small white daisies cover the long-blooming Snowbank white boltonia (Boltonia asteroides 'Snowbank') from very late summer through fall. The billowy mounds of foliage on this cultivar top out at 4 feet in size (in comparison to the species, which can grow 5 to 6 feet tall). Grow in full sun, in low-fertility soils, and water only during the most severe droughts once the root system is established. This boltonia is a butterfly magnet.